Integrated circuit card with two connection modes

ABSTRACT

An integrated circuit card with two connection modes. The integrated circuit card includes a card body in which there is embedded a link circuit for linking a contactless coupling element ( 1 ) to a module having an integrated circuit ( 6 ) connected to conductive areas carried by a support film ( 4 ). The link circuit extends in register with conductive areas ( 18 ) dedicated to making a contactless link and is connected to said conductive areas by an electrically conductive material ( 32, 36, 42 ) filling blind holes ( 31, 35, 41 ). The blind holes have sections that increase from a bottom of each hole towards an opening thereof over at least a portion of their height.

BACKGROUND OF THE INVENTION

The present invention relates to an integrated circuit card having twoconnection modes.

A card with two connection modes means a card capable of being connectedto a device either via a link involving contact, i.e. a metallic linkvia contact areas flush with the outside surface of the card, or elsevia a contactless link. For the contactless link, the card includes acontactless coupling element such as an induction loop, a radio antenna,or an optical coupling member connected via a link circuit embedded inthe card to an interface that is generally contained in the integratedcircuit.

Document EP 682 321 discloses an integrated circuit card having twoconnection modes comprising a card body in which there is embedded anantenna connected to a module comprising an integrated circuit connectedto conductive areas carried by a support film, the antenna having endsin register with the conductive areas. That document provides for theconductive areas of the module to be put directly into contact with theends of the antenna. That poses a problem, since module positioning mustbe extremely accurate, and is therefore incompatible with manufacturingat a high rate of throughput.

OBJECT AND SUMMARY OF THE INVENTION

The present invention relates to various embodiments making it possibleat low cost and at a high throughput rate to provide links between thelink circuit of a contactless coupling element and a module comprisingan integrated circuit connected to conductive areas carried by a supportfilm.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of the invention appear on readingthe following description of numerous particular and non-limitingembodiments of the invention all relating to the same inventive idea,and given with reference to the accompanying figures, in which:

FIG. 1 is an exploded perspective view of the sheets constituting thebody of the card in an embodiment of the invention;

FIG. 2 is a fragmentary section view on a larger scale on line II—II ofFIG. 1 during an intermediate step in making a first embodiment of acard of the invention;

FIG. 3 is a section view analogous to that of FIG. 2, in a later step;

FIG. 4 is a partially cutaway perspective view of an integrated circuitmodule corresponding to the first embodiment of the invention;

FIG. 5 is a section view analogous to that of FIG. 2, after theintegrated circuit module has been put into place;

FIG. 6 shows a variant associated with the first embodiment; and

FIGS. 7 to 19 are fragmentary section views of various other embodimentsof the invention.

MORE DETAILED DESCRIPTION

With reference to FIGS. 1 to 6, in the first embodiment, the integratedcircuit card of the invention with two connection modes is made from acontactless coupling element in the form of an antenna 1 carried by asupport sheet 2, and a module given general reference 3 (see FIGS. 4 and5) comprising a support film 4 fitted with conductive areas 5 connectedto an integrated circuit 6 by wires 7 to provide links by contact, andconductive areas 18 connected to the integrated circuit 6 by wires 19 toprovide links with a contactless interface included in the integratedcircuit 6. The integrated circuit 6 and the link wires 7 and 19 areembedded in a block of resin 8.

The antenna 1 has two ends adjacent to each other forming a link circuitfor linking the contactless coupling element as constituted by theantenna with the conductive areas 18 of the module. For an opticalcoupling element, this link circuit would be constituted by conductivetracks extending in analogous manner on a support sheet. By way ofexample, the link circuit would be constituted by copper tracks madeusing conventional printed circuit techniques.

In this first embodiment of the invention, link pads 11 are formed onthe ends of the antenna and project from the ends of the antenna (seeFIG. 2). The link pads 11 may be made by silkscreen printing aconductive polymer or by mechanically depositing a drop of metal. Theymay also be made in the form of electrolytic deposits, or by usingadhesive (a conductive adhesive), or by soldering a metal pad on thelink printed circuit, or indeed by chemical etching or mechanicallymachining a thick track.

In this embodiment, the conductive areas 18 are carried by the outsideface of the module 3. The support film 4 of the integrated circuitmodule 3 has holes 9 facing the contact areas 18 and provided withconnection pads 10, e.g. made of a conductive material comprising apolymer containing conductive grains, and projecting from a face of thesupport film 4 facing away from the contact areas 18. For connectionpads 10 made of conductive material, the material is preferably in aplastic state prior to the module being incorporated in the integratedcircuit card of the invention.

In order to make it possible to provide links between the conductiveareas 18 of the module and the ends of the antenna 1, the holes 9 in thesupport film of the module are made in a disposition that enables themto be put into register with the link pads 11 when the integratedcircuit module 3 is implanted in the card.

In the embodiment shown, the support sheet 2 for the antenna 1 is madeout of a reinforced synthetic material, e.g. an epoxy resin reinforcedby glass fibers or polyester fibers, and the antenna 1 is made in theform of a printed circuit on the support sheet 2. In this embodiment,the support sheet 2 has an opening 12 of transverse dimension D greaterthan the transverse dimension d of the resin block 8 containing theintegrated circuit 6 (FIG. 5).

To make the card of the invention as shown in FIG. 5, the support sheet2 for the antenna 1 is initially covered on both faces with sheets ofinsulating material 13. Sheets of thermoplastic material such as PVCare, for example, pressed against the support sheet 2 by hot-rolling sothat the sheets of insulating material 13 adhere to the support sheet 2and flow so as to fill the opening 12 through the support sheet 2 inuniform manner. The material filling the opening 12 also serves to embedthe support sheet 2 in the mass of thermoplastic material formed bysoftening the sheets 13. A sandwich structure is thus obtained as shownin section in FIG. 2.

A cavity given general reference 14 is then dug out in the card bodyformed in this way (FIG. 3). The cavity 14 has a central portion 15 ofrelatively small diameter and large depth for receiving the resin block8 of the module 3, and a peripheral portion 6 of larger diameter andshallower depth for receiving the support film 4 and the conductiveareas 5 of the module 3. In this respect, it will be observed that theheight of the link pads 11 is designed so that when the portion 16 ofthe cavity is made, the antenna link pads 11 extend into the bottom ofthe cavity. By making link pads that project from the ends of theantenna, it is possible to machine the cavity with ordinary toleranceswithout running the risk of damaging the antenna. In this context, itshould be observed that given the accuracy with which the link circuitis positioned on the support sheet and given the tolerances with whichthe cavity is made, it turns out at present that an extra thickness ofonly 70 micrometers suffices.

It should also be observed that making an opening 12 in the supportsheet 2 of transverse dimension greater than the transverse dimension ofthe resin block of the module 3 makes it possible to form the cavity ina mass of uniform material, thereby making it possible to use a toolthat is specifically adapted to said material. Furthermore, the uniformthermoplastic material surrounding the portion 15 of the cavity servesto embed the edge of the opening 12 through the support sheet 2, therebyproviding the card with better strength against the forces to which itis subjected during various operations, whether during manufacture or inuse. The sheets 13 are preferably of thicknesses that are determined sothat after rolling, the antenna 1 lies in the vicinity of the neutralfiber of the card. This avoids the card body bending phenomena thatresult from differential expansion when the antenna 1 is not on theneutral fiber. The antenna 1 or the link circuit of the contactlesscoupling element can also be made directly on a sheet of thermoplasticmaterial. In this context, it should nevertheless be observed thatduring rolling, the pads 11 constitute non-uniform masses which tend tobe shifted towards the center of the card as shown in FIG. 6 under theeffect of the pressure applied to the plastics material while it isflowing. This deformation causes the thermoplastic material to flow to agreater extent in register with the pads 11. This distorts thedecoration which is generally printed on the outside faces of the sheets13. To avoid such deformation, it is therefore advantageous to provideintermediate sheets 20 carrying decoration and having a softeningtemperature which is higher than that of the rolling temperature. Theintermediate sheets 20 are coated in an adhesive that is activatable byapplying heat and may preferably be covered in transparent protectivesheets 21.

After the cavity has been made, the module 3 is implanted in the card,e.g. by placing a small quantity of adhesive 17 in the bottom of thecavity, which adhesive spreads out in the gap between the block of resin8 and the wall of the cavity 14. While the module 3 is being put intoplace in the card body, the conductive material 10 placed in the holes 9of the support film 4 is compressed as shown in FIG. 5 and providescontact with the link pads 11, thus forming conductive members betweenthe conductive areas 18 and the antenna 1. As shown in FIG. 5, thecompressed connection pads 10 project laterally from the holes 9 so asto provide sufficient contact with the pads 11 even if they are notexactly in register therewith when the module is put into place. Whenthe conductive material 10 is in a plastic state prior to the modulebeing put into place, it is preferable, once the module is in place, toprovide for the conductive material to harden with temperature so as toensure greater reliability of the connection. In this context, it shouldbe observed that in this embodiment the conductive areas 18 which areconnected to the ends of the antenna, even though they face towards theoutside of the module, i.e. away from the integrated circuit 6, need notbe used for making contact with a machine. Under such circumstances, theconductive areas 18 which are connected to the antenna are used only forproviding a bridge between the ends of the antenna and the correspondingwires 19.

FIG. 7 shows a second embodiment in which the conductive areas 18serving to provide a bridge between the integrated circuit 6 and theends of the antenna are disposed this time on the same face of thesupport film 4 as carries the integrated circuit 6.

In this case, the module preferably has holes 22 in register with theconductive areas 18, which holes enable a heating tool to be put intocontact with the conductive areas 18 when the module is put into place.The connection pads 10 and the link pads 11 which serve to connect theconductive areas 18 to the ends of the antenna 1 are then advantageouslymade of a meltable conductive material, e.g. a conductive materialincluding metal grains having different melting point& as described indocument FR-A-2 726 001, thereby making it possible to provide bondingat high temperature and to obtain a link of particularly low electricalresistance between the conductive areas and the antenna.

Also, in this embodiment, the module is fixed by an elongate bead ofadhesive 23 disposed in the bottom of the portion 16 of the cavity 14,which bead is interrupted in register with the link pads 11.

This connection can also be made by depositing a drop of conductivepolymer on the end of the pad 11 that is visible in the bottom of thecavity prior to the module being fixed in the cavity. In which case theconductive area 18 is not provided with a connection pad 10. In bothcases and for the purpose of defining the location of the adhesive andthe location of the conductive material, it is preferable to formgrooves in the bottom of the portion 16 of the cavity as shown in FIG. 6which is a plan view of the cavity prior to the module being put intoplace. Grooves 24 are provided to extend across the ends of the pads 11,and grooves 25 are formed on either side of the grooves 24. The depthsof the grooves 24 and 25 are adapted to the kinds of substances used sothat the facing surfaces are appropriately wetted by the correspondingsubstances when the module is put into place. In particular, when theconductive material is fixed on the contact areas of the module, it isimportant for the grooves 24 to be deeper than the grooves 25 so thatthe conductive material does not constitute an obstacle to makingcontact with the portions of the module facing the adhesive.

FIG. 9, which is a fragmentary section view of the card through the linkbetween the module and the link circuit of the contactless couplingelement, shows a variant of this embodiment. In this variant, theconductive area 18 is carried by the outside face of the support film 4which then has holes in register with the pads 11. A conductive pad 26,which may be rigid or of thermoplastic material, is fixed in each holeof the film and is surfaced so that its bottom face is flush with thebottom surface of the film. The link between the pad 26 and the pad 11is provided by a drop of thermoplastic material 27.

In the embodiment of FIG. 5, as in the embodiment of FIG. 7, it is alsopossible to provide a lug 10 of rigid conductive material which isheated while the module is being put into place and which thenpenetrates into a link pad 11 of hot-melt conductive material.

FIG. 10 shows another variant in which the link between the conductivearea 18 and the pad 11 is provided by a conductive elastic insert 28,e.g. an insert made of an elastomer that has been made conductive in itsbulk or that has been covered in a conductive coating or a conductivepowder.

FIG. 11 shows another variant embodiment in which the support film 4 andthe conductive area 18 are pierced by a hole which opens out to theoutside surface of the module. A drop of hot-melt conductive polymer ora conductive elastic insert 29 is placed on the pad 11 prior to themodule being put into place. After the module has been put into place,this disposition makes it possible to level off the conductive materialwhich projects from the hole to the outside of the module. It is alsopossible to insert conductive material (in solid or semi-solid form)into the hole after the module has been mounted on the card.

For the contact areas 5 and 18 in register with each other as shown inFIG. 11, it is nevertheless appropriate to insulate the edge of the holein the contact area 5 or to use a conductive element that does not reachthe contact area 5 or that includes an insulating portion facing thecontact area 5 so as to avoid making a short circuit between theconductive areas 5 and 18.

FIG. 12 shows a third embodiment in which the antenna 1 is no longercarried by an epoxy resin support sheet sandwiched between twothermoplastic sheets, but is made directly on a thermoplastic sheetwhich it then suffices to cover on its antenna-carrying face withanother sheet of the same kind so as to obtain a card body of uniformmaterial.

In addition, in this third embodiment, the links between the conductivepads 18 and the antenna 1 are provided by rigid conductive members, inthis case screws 30 which pass through the conductive areas 18 and thecorresponding ends of the antenna 1. In this case, the conductive memberis put into place after the module has been fixed in the cavity of thecard.

FIG. 13 shows a variant embodiment in which this embodiment of the linksby means of rigid members passing through the layers to be connectedtogether is used in association with an antenna 1 that is fitted with aconnection pad 11 projecting from the antenna. This increases thecontact area between the screw 30 and the end of the antenna forming theantenna link circuit.

FIG. 14 shows another embodiment in which a conductive member isinserted in a hole that opens out in the surface of the card and thatpasses through the antenna without the antenna being previously fittedwith a connection pad 11.

In this embodiment, the module is put into place before a link is made,as in the cases of FIGS. 12 and 13, and then respective holes 31 aremade through the portions of the module and of the card that overlie theends of the antenna, and through said ends, i.e. the holes 31 passthrough the link circuit and the associated conductive areas 18. Theholes made in this way are filled with conductive material which can beeither in the form of a rigid insert of complementary shape engaged byforce or held by a helical thread, or a conductive material inserted inthe semi-solid state, or rigid inserts in association with semisolidmaterial, or indeed a conductive elastic material. In the embodiment ofFIG. 14 the blind hole 31 is conical. This shape has the advantage ofincreasing the contact area between the conductive link members and theconductive areas through which they pass. In particular, given the verysmall thicknesses of the various layers passed through, it is possibleindustrially to make a conical hole having an angle at the apex of 120°,thereby doubling the area of contact with the layers passed through.

In addition, a conical hole makes it possible visually to inspect thequality of the hole formed using a simple camera in order to make sure,in particular, that no swarf is present and in order to verify thesurface state of the conductive layers passed through.

In addition, a conical hole, or more generally a blind hole of sectionthat increases from the bottom end of the hole to its open end, iseasier to fill than a cylindrical hole and provides automatic centeringof the inserted conductive material, whether it is rigid or semi-solid,thus making it possible to increase positioning tolerance for the toolsused for putting the conductive material into place.

In order to mask the conductive material, it is it possible to cover itwith a metal land or with an ink of color analogous to that of thesurface of the card at the location where the hole opens out to thesurface thereof.

When the conductive material is semi-solid, it is possible to use amaterial that is naturally conductive in the semi-solid state or amaterial that is caused to become conductive by heating or after curing.

FIG. 15 shows a variant of this type of link. In this variantembodiment, the blind hole 31 is cylindrical and the conductive materialfilling the hole is an association of a conductive material 33 insertedin the semi-solid state, plus a rigid insert 34 inserted into thesemi-solid material. This solution combines the advantages of the lowresistivity of the rigid insert with the good contact made by thesemi-solid material with all of the exposed surfaces. In this context,it is advantageous to use the conductive ink described inabove-mentioned document FR-A-2 726 001 together with a heated insertwhich serves to melt the metal grains of lower melting point and whichsimultaneously compensates for the reduction in volume that results fromsuch melting.

FIG. 16 shows yet another type of link consisting in making a blind hole35 in the card body and through the end of the antenna 1 after thecavity 14 has been made but before the module is mounted, and then ininserting a conductive link member in the hole. In the embodiment ofFIG. 16, the blind hole 35 is conical and the link member is in the formof a block of material that was inserted in the semi-solid state andthen cured, and that projects slightly from the bottom of the cavityover a thickness substantially equal to the thickness of the adhesiveserving to fix the module in the cavity (the thickness of the projectioncan be controlled by machining). While the module is being mounted, theblind hole 31 is thus put simultaneously into contact with theconductive area 18 of the module. It is also possible to press a hotpunch over the pad 36 so as to finish off its connection with theconductive area 18. It is also possible to make this type of link bypawing an elastic conductive member in the hole 35.

FIG. 17 shows a variant of this embodiment which consists in fixing arigid insert, in this case a screw 37, in the bottom of the cavity 14 sothat the insert 37 passes through the end of the antenna 1 and extendsso as to project slightly from the bottom of the cavity, with theprojecting portion then being covered in conductive material 38 so as toprovide good contact with the conductive area 18.

FIG. 18 shows an embodiment using an anisotropic adhesive 39 for fixingthe module in a cavity into which there extends a link pad 11 associatedwith one end of the antenna, and then in subjecting the adhesive tolocalized pressure in register with the link pad 11 so as to make thecorresponding portion 40 of the adhesive 39 conductive. Thus whilenevertheless using a continuous elongate bead of anisotropic adhesive ora washer of anisotropic adhesive to provide uniform fixing for themodule, it is still possible to obtain localized conduction in this way.

FIG. 19 shows an embodiment in which the blind hole 41 passing throughthe body of the card and the end of the link circuit is in the form of aspherical cap, or more generally of concave curvilinear section (whichcould be in the form of a paraboloid or an ellipsoid). This shapedefines a larger volume than does a conical hole, thereby making itpossible to increase tolerance on the volume of the drop of conductivematerial 42 which is inserted into the hole, while neverthelessconserving a satisfactory link between the link circuit and theassociated conductive area 18.

Naturally, the invention is not limited to the embodiments described andvariants can be made thereto without going beyond the ambit of theinvention, as defined by the claims.

In particular, the various embodiments of the card body and of themodule can be combined in assemblies other than those shown.

The support sheet 2 and the covering sheets 13 are preferably made inthe form of continuous strips, possibly provided with lateralperforations (not shown) so as to make a series of cards by sequentiallydisplacing the strips through successive workstations.

What is claimed is:
 1. An integrated circuit card with two connectionmodes, including a contact mode by contact areas (5) flush with anoutside surface of the card and a contactless mode using a contactlesscoupling element (1), said integrated circuit card comprising a cardbody in which there is embedded a link circuit for linking a contactlesscoupling element (1) to a module comprising an integrated circuit (6)connected to conductive areas carried by a support film (4), the linkcircuit extending in register with conductive areas (18) dedicated tomaking a contactless link and being connected to said conductive areasby an electrically conductive material (32, 36, 42) filling blind holes(31, 35, 41) of section that increases from a bottom of each holetowards an opening thereof over at least a portion of their height.
 2. Acard according to claim 1, wherein the holes pass through the linkcircuit.
 3. A card according to claim 1, wherein the holes are conical.4. A card according to claim 3, wherein the conical holes have an angleat the apex of 120°.
 5. A card according to claim 1, wherein theconductive material (36, 42) projects relative to the holes (35, 41). 6.A card according to claim 1, wherein the holes are of a concavecurvilinear shape.
 7. A card according to claim 6, wherein the holes arehemispherical.
 8. A card according to claim 1, wherein the holes (31)extend through the support film.
 9. A card according to claim 1, whereinthe support film includes blind holes (22) in register with thededicated conductive areas and opening out in a face of the modulefacing away from the integrated circuit.